The present invention relates to a surface discharge type AC-driven plasma display panel, particularly to the discharge cell structure of such plasma display panel.
Recently, there has been appeared in the market a new type of display device which is large in size and small in thickness, with one example being a surface discharge type AC-driven plasma display panel.
FIG. 47 is a plane view schematically indicating a surface discharge type AC-driven plasma display panel made according to a prior art. FIG. 48 is a sectional view taken along line Vxe2x80x94V in FIG. 47, FIG. 49 is a sectional view taken along line Wxe2x80x94W in FIG. 47.
As shown in FIGS. 47-49, the conventional plasma display panel has a front glass substrate 1 (serving as a displaying surface), a plurality of row electrode pairs (Xxe2x80x2, Yxe2x80x2), a dielectric layer 2 covering the row electrode pairs (Xxe2x80x2, Yxe2x80x2), a protection layer 3 consisting of MgO covering the dielectric layer 2.
Referring to FIG. 47, each row electrode pair (Xxe2x80x2, Yxe2x80x2) includes a pair of transparent electrodes (Xaxe2x80x2, Yaxe2x80x2) consisting of ITO transparent electrically conductive film and having a relatively large width, and a pair of bus electrodes (Xbxe2x80x2, Ybxe2x80x2) consisting of a metal film having a relatively small width. The bus electrodes (Xbxe2x80x2, Ybxe2x80x2) are provided to compensate for the electric conductivity of the transparent electrodes (Xaxe2x80x2, Yaxe2x80x2).
Further, two row electrodes forming each row electrode pair (Xxe2x80x2, Yxe2x80x2) are arranged in parallel with each other, forming a discharge gap gxe2x80x2 therebetween, thereby forming one displaying line L for the plasma display panel (matrix display)
Referring to FIGS. 48 and 49, the conventional plasma display panel has a rear glass substrate 4 arranged space-apart from the front glass substrate 1, thereby forming an electric discharge space Sxe2x80x2 therebetween. Further, the display panel includes a plurality of column electrodes Dxe2x80x2 arranged orthogonal to the row electrodes (Xxe2x80x2, Yxe2x80x2), a plurality of belt-like partition walls 5 provided between and in parallel with the column electrodes Dxe2x80x2, a fluorescent layer 6 including three kinds of original color portions 6(R), 6(G), 6(B). In detail, the fluorescent layer 6 is so provided that it covers the side surfaces of the partition walls 5 and the column electrodes Dxe2x80x2.
In this way, the row electrode pairs (Xxe2x80x2, Yxe2x80x2) are intersected with the column electrodes Dxe2x80x2, while the discharge space Sxe2x80x2 is divided by the partition walls 5 into a plurality of smaller sections, thereby forming a plurality of electric discharge cells Cxe2x80x2 serving as a plurality of light emission units, as shown in FIG. 47.
A displaying process of the surface discharge type AC-driven plasma display panel having the structure shown in FIGS. 47-48 will be described in the following.
At first, an addressing operation is conducted so that an electric discharge is effected selectively among the discharge cells Cxe2x80x2 between the row electrode pairs (Xxe2x80x2, Yxe2x80x2) and the column electrodes D. As a result, a plurality of lit-up cells (discharge cells Cxe2x80x2 where wall charges have been formed in the dielectric layer 2) and a plurality of extinguished cells (discharge cells Cxe2x80x2 where wall charges are not formed in the dielectric layer 2) are distributed on the panel corresponding to a picture to be displayed.
Subsequently, discharge sustaining pulses are simultaneously applied to all the displaying lines L in a manner such that the row electrode pairs (Xxe2x80x2, Yxe2x80x2) will alternatively receive the discharge sustaining pulses. In this manner, surface discharge phenomenon will occur in lit-up cells once the discharge sustaining pulses are applied thereto.
At this moment, since ultraviolet light will be generated due to the surface discharge in the lit-up cells, the fluorescent layer 6 (R, G, B) will be excited to effect light emission, thereby displaying a picture on the plasma display panel.
In the above-described surface discharge type AC-driven plasma display panel, since a fluorescent layer 6 has been provided to cover not only the column electrodes Dxe2x80x2 but also the side faces of the belt-like partition walls 5, a light emission area within each discharge cell Cxe2x80x2 has been increased, thus increasing the brightness of a picture being displayed on the panel.
However, with the above-described surface discharge type AC-driven plasma display panel, if it is desired to improve the fineness of a displayed picture by reducing the size of each discharge cell Cxe2x80x2, a total surface area of the fluorescent layer 6 will also be undesirably reduced, resulting in a deterioration in the brightness of the displayed picture.
To cope with the above problem, it is allowed to consider making narrow the pitch between each row electrode pair (Xxe2x80x2,Yxe2x80x2). This, however, would cause a problem called discharge interference between every two adjacent discharge cells Cxe2x80x2, hence resulting in some misdischarges.
It is a first object of the present invention to provide an improved plasma display panel capable of ensuring an improved fineness for a picture being displayed on the panel, without causing the above-mentioned problems such as a decrease in a displaying brightness and some misdischarges in discharge cells.
It is a second object of the present invention to provide an improved plasma display panel capable of preventing a reflection of an external light incident on the panel, thereby improving the contrast of a picture being displayed on the panel.
It is a third object of the present invention to provide an improved plasma display panel capable having an improved resolution.
It is a fourth object of the present invention to provide an improved plasma display panel capable of preventing a warpage in partition walls (which are provided to divide a discharge space into a plurality of discharge cells), thereby preventing a possible deformation in the predetermined shape of the discharge cells.
It is a fifth object of the present invention to provide an improved plasma display panel capable of preventing the formation of unwanted slots between a front glass substrate and a rear glass substrate, thereby avoiding any possible defect caused by such slots in the display panel.
According to the present invention, there is provided a plasma display panel comprising: a front substrate; a plurality of row electrode pairs provided on the inner surface of the front substrate, said row electrode pairs being arranged in parallel with one another and extending in the row direction of the panel, with each row electrode pair forming a displaying line; a dielectric layer provided on the inner surface of the front substrate for coverring the row electrode pairs; a rear substrate arranged in parallel with and space-apart from the front substrate, forming a discharge space therebetween; a plurality of column electrodes provided on the inner surface of the rear substrate, said column electrodes being arranged in parallel with one another and extending in the column direction of the panel, in a manner such that at each intersection of a row electrode pair with a column electrode there is for med a light emission unit; a partition wall assembly provided between the front substrate and the rear substrate, said partition wall assembly including a plurality of longitudinal partition walls and a plurality of lateral partition walls, thereby dividing the discharge space into a plurality of discharge cells. In particular, the dielectric layer has a plurality of projection portions located corresponding to and protruding toward the lateral partition walls of the partition wall assembly, in a manner such that there would be no slots formed between the dielectric layer and the lateral partition walls.
In one more aspect of the present invention, a slot is formed between the dielectric layer and each longitudinal partition wall of the partition wall assembly.
In one more aspect of the present invention, a fluorescent layer is formed to cover side faces of the longitudinal partition walls and the lateral partition walls and exposed portions of another dielectric layer formed on the inner surface of the rear substrate
In one more aspect of the present invention, the partition wall assembly has a two-layer structure, one of which is a light absorbing layer located closer to the front substrate, and the other of which is a light reflecting layer located closer to the rear substrate.
In one more aspect of the present invention, each row electrode pair has two row electrodes each having a light absorbing layer facing the front substrate
In one more aspect of the present invention, each of the two row electrodes forming one electrode pair has a plurality of protruding portions, forming a plurality of discharge gaps between mutually facing protruding portions of the two row electrodes.
In one more aspect of the present invention, a mutual positional relationship between two row electrodes of a row electrode pair is alternatively changed from one displaying line to another, two mutually adjacent row electrodes of every two mutually adjacent displaying lines are connected to an identical common electrode main body.
In one more aspect of the present invention, protruding portions of two mutually adjacent row electrodes of every two mutually adjacent displaying lines are connected with each other.
In one more aspect of the present invention, there are formed a plurality of lateral light absorbing straps on the inner surface of the front substrate, with each lateral light absorbing strap being positioned between two mutually adjacent row electrodes of every two mutually adjacent displaying lines.
In one more aspect of the present invention, there are formed a plurality of longitudinal light absorbing straps on the inner surface of the front substrate, with each longitudinal light absorbing strap being positioned corresponding to one longitudinal partition wall.
In one more aspect of the present invention, a light absorbing layer is formed on the inner surface of the front substrate layer, said light absorbing layer having the same pattern corresponding to the lateral and longitudinal partition walls of the partition wall assembly.
In one more aspect of the present invention, protruding portions of two row electrodes forming one displaying line have mutually facing head portions which are inclined with respect to the row direction of the panel.
In one more aspect of the present invention, each displaying line includes a plurality of discharge cells repeatedly arranged in the order of R, G, B, each column includes a plurality of same color discharge cells, with every three discharge cells (R, G, B) arranged in a display line forming one picture element.
In one more aspect of the present invention, each displaying line includes a plurality of discharge cells repeatedly arranged in the order of R, G, B, one displaying line being deviated in the row direction from its adjacent displaying line by one discharge cell, with every three discharge cells (R, G, B) arranged in a display line forming one picture element.
In one more aspect of the present invention, each displaying line includes a plurality of discharge cells repeatedly arranged in the order of R, G, B, one displaying line being deviated in the row direction from its adjacent displaying line by half width of one discharge cell, with every three discharge cells (R, G, B) arranged in a display line forming one picture element.
In one more aspect of the present invention, each displaying line includes a plurality of discharge cells repeatedly arranged in the order of R, G, B, one displaying line being deviated in the row direction from its adjacent displaying line by 1.5 times the width of one discharge cell, in a manner such that each pitch element may also be formed by three discharge cells (R, G, B) which together form a triangular configuration bridging over two mutually adjacent displaying lines.
In one more aspect of the present invention, each lateral partition wall of the partition wall assembly is divided into two portions by an elongated slot extending in the row direction of the panel.
In one more aspect of the present invention, each divided portion of each lateral partition wall has substantially the same width as that of each longitudinal partition wall of the partition wall assembly.
In one more aspect of the present invention, a plurality of light absorbing straps are formed on the inner surface of the front substrate, in positions corresponding to the elongated slots.
In one more aspect of the present invention, a plurality of light absorbing straps are formed on the inner surface of the front substrate, in positions corresponding to the longitudinal partition walls of the partition wall assembly.
In one more aspect of the present invention, at least the longitudinal partition walls of the partition wall assembly have a two-layer structure, one of which is a light absorbing layer facing toward the front substrate, and the other of which is a light reflecting layer facing toward the rear substrate.
In one more aspect of the present invention, each of two row electrodes of a row electrode pair includes an elongated main body portion extending in the row direction of the panel and a plurality of protruding portions extending in the column direction of the panel, so that a plurality of discharge gaps are formed between mutually facing protruding portions of two elongated main body portions. In particular, each elongated main body portion is made by a metal film. Further, each protruding portion is formed by a transparent electrically conductive film, with its base end connected to an elongated main body portion.
In one more aspect of the present invention, a light absorbing layer is formed on each elongated main body portion so that said light absorbing layer is interposed between the inner surface of the front substrate and the elongated main body portion.
In one more aspect of the present invention, one elongated main body portion is shared by two mutually adjacent row electrodes of two mutually adjacent displaying lines.
In one more aspect of the present invention, the outermost corner portions of each lateral partition wall are removed so as to form inclined surfaces thereon.
In one more aspect of the present invention, outer end portions of partition wall assembly are formed in positions not facing the projection portions of the dielectric layer.
In one more aspect of the present invention, outer end portions of each pair of lateral partition walls are combined with each other in positions not facing the projection portions of the dielectric layer.
In one more aspect of the present invention, the partition wall assembly is made of a light transmissible material.
In one more aspect of the present invention, each of two row electrodes of one row electrode pair has a plurality of protruding portions, thereby forming a plurality of discharge gaps between mutually facing protruding portions of the two row electrodes. Further, a mutual positional relationship between two row electrodes of one row electrode pair is alternatively changed from one displaying line to another. Moreover, one common electrode main body portion is shared by two mutually adjacent row electrodes of two mutually adjacent displaying lines.